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791.
Models are sometimes developed on the premise that there are no differences between two or more conditions regardless of experimental manipulation. This article argues that unless a very sensitive experiment (or series of experiments) was conducted, such conclusions are often premature. Design and statistical factors such as alpha level, variability, sample size, and treatment effect are all determinants of the sensitivity of the experiment. It is sometimes the case that an experiment produces differences between means and yet the null hypothesis is not rejected because of high variability within experimental conditions or because too few subjects were used. Unless the probability of detecting a difference between groups is known, it would seem unwise to conclude that no difference exists. Judgment on the model should be suspended. Examples are taken from the mass-spring and pulse-step models fro voluntary movement control to illustrate the problem. 相似文献
792.
A detailed kinematic and electromyographic (EMG) analysis of single degree of freedom timing responses is reported to (a) determine the coherence of kinematic and EMG variability to the reduced timing error variability exhibited with amplitude increments within a given criterion movement time and (b) understand the temporal organization of various movement parameters in simple responses. The data reveal that the variability of kinematic (time to peak acceleration, duration of acceleration phase, time to peak deceleration) and EMG (duration of agonist burst, duration of antagonist burst, time to antagonist burst) timing parameters decreased with increments of average velocity in a manner consistent with the variable timing error. In addition, the coefficient of variation for peak acceleration, peak deceleration, and integrated EMG of the agonist burst followed the same trend. Increasing average movement velocity also led to decreases in premotor and motor reaction times. Overall, the findings suggest a strong coherence between the variability of response outcome, kinematic, and EMG parameters. 相似文献
793.
This study compared central nervous system organizational processes underlying balance in children of three age groups: 15-31 months, 4-6 years, and 7-10 years, using a movable platform capable of antero-posterior (A-P) displacements or dorsi-plantar flexing rotations of the ankle joint. A servo system capable of linking platform rotations to A-P sway angle allowed disruption of ankle joint inputs, to test the effects of incongruent sensory inputs on response patterns. Surface electromyography was used to quantify latency and response patterns. Surface electromyography was used to quantify latency and amplitude of the gastrocnemius, hamstrings, tibialis anterior, and quadriceps muscle responses. Cinematography provided biomechanical analysis of the sway motion. Results demonstrated that while directionally specific response synergies are present in children under the age of six, structured organization of the synergies is not yet fully developed since variability in timing and amplitude relationships between proximal and distal muscles is high. Transition from immature to mature response patterns was not linear but stage-like with greatest variability in the 4- to 6- year-old children. Results from balance tests under altered sensory conditions (eyes closed and/or ankle joint inputs altered) suggested that: (a) with development a shift in controlling inputs to posture from visual dependence to more adult-like dependence on a combination of ankle joint and visual inputs occurred in the 4- to 6-year-old, and reached adult form in the 7- to 10-year-old age group. It is proposed that the age 4-6 is a transition period in the development of posture control. At this time the nervous system (a) uses visual-vestibular inputs to fine tune ankle-joint proprioception in preparation for its increased importance in posture control and (b) fine tunes the structural organization of the postural synergies themselves. 相似文献
794.
The role played by reflex pathways in the production of movement has been a significant issue for motor control theorists interested in a wide variety of motor behaviors. From studies of locomotion and chewing, it appears that gains in reflex pathways can be altered so that activity in these pathways does not produce destabilizing responses during movement. In speech production, recent experimental evidence has been interpreted to suggest that autogenetic lip reflexes (perioral reflexes) are suppressed during sustained phonation or speech production. The present study was conducted to assess the effects of phonation, direction of movement, and ongoing speech production on reflex responses of lip muscles. The present results suggest, in contrast to earlier work, that this reflex pathway is not suppressed or absent because the amplitude of the observed response depends upon the activation levels of the various muscles of the lower lip and, therefore, indirectly on the nature of the gesture the subject is instructed to produce. 相似文献
795.
Checklists of children's nighttime fears and nighttime coping responses, completed by 178 8- to 13-year-old children and one of their parents, were factor analyzed. The resulting factors from each checklist were comparable for children and parents. The nighttime fear categories consisted of content around security either for one's personal life, loss, or safety or for others' safety and continued presence; imaginal-numinous concerns; and characteristics inherent in a nighttime situation. The coping categories consisted of responses related to internal self-control, social support, support from inanimate objects, prayer, and avoidance or escape either by controlling the inanimate environment or by controlling others. 相似文献
796.
A M Gross H K Delcher J Snitzer B Bianchi S Epstein 《The Journal of genetic psychology》1985,146(1):19-26
Insulin-dependent diabetic children and a group of their nondiabetic peers were compared on measures of self-concept, locus of control and health locus of control. A metabolic measure of long term diabetes control was also obtained on the children with diabetes. Data analyses revealed that metabolic control was not related to any of the personality measures in the diabetic sample. Diabetic and non-diabetic children did not differ on measures of locus of control and self-concept, but diabetics exhibited a health locus of control which was significantly more internal than that of control subjects. A possible explanation for these results was discussed and practical implications for health care providers working with young diabetics were presented. 相似文献
797.
Theodore M Alper 《Journal of mathematical psychology》1985,29(1):73-81
Real relational structures of scale type (1, 2) can be represented in the reals in such a way that the induced automorphism group is properly contained in the affine group and itself properly contains the group of translations. There are no real relational structures of scale type (m, m + 1), m ≥ 2. 相似文献
798.
Extended the literature on age differences on the Hand Test using a multivariate model to examine absolute and relative differences in response. Participants were 47 adults (M age = 22.47 yrs.), 24 males and 23 females; and 45 older adults (M age = 64.87 yrs.), 21 males and 24 females. Data were analyzed in terms of percentage of response and absolute frequency of specific responses, between the age groups. Results indicated similar findings to those previously reported for the Hand Test, though magnitude of personality deterioration or withdrawal was lessened, for the percentage analysis. Results indicated the importance of using both absolute frequency of response and percentage of response in the interpretation of projective test data, especially for older adults. 相似文献
799.
The residual effects of severe closed head injury on psychological functioning, as determined by data from the Rorschach test, were examined. Thirty-five young adult patients with severe closed head injury were compared to a nonpatient, non-head injured matched group sample of 36 subjects. The utility of the Rorschach test in distinguishing the characteristic psychological functioning of inpatients who have suffered from severe closed head injury was outlined. The apperceptive disturbance, affective/cognitive problems, and interpersonal difficulties were discussed. 相似文献
800.